An optical see-through glass type display device provides a viewer with a virtual image superimposed onto an ambient scene seen through the glass. The virtual image may be projected by a projector and guided into an eye of the viewer via an optical element on the glass. The optical see-through glass type display device may present a stereoscopic virtual image by displaying a left image on the left glass and a right image on the right glass of the device so that the viewer can experience a three-dimensional perception of depth.
In such an optical see-through glass type display device, it is preferable for the viewer to perceive the virtual image in spatial coherence with the ambient scene image even if the device comprises corrective surfaces providing a prescription glasses function in order to present the virtual image on the ambient scene image in proper position and size as well as in proper depth if the virtual image is a stereoscopic virtual image.
EyeTap Personal Imaging (ePI) Lab, a research laboratory from University of Toronto, developed the “EyeTap” technology which combines a display and camera in an eyewear for preserving correspondence between the real world and the virtual world through the use of a flat beam splitter plate. However, this technology is not directed to a situation in which the eyewear comprises prescription glasses.